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Ocular
Microbiology and Immunology Group
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2015
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2015
OMIG Abstract 10
Ocular Pathogens and Antibiotic Sensitivity of Bacterial Keratitis Isolates at
King Khaled Eye Specialist Hospital, Saudi Arabia - 2011-2014
Donald U. Stone, M.D.1,2, Huda Al Dhaheri M.D.1, Mashael Tamimi M.D.1
Mohammed Khan Ph.D.1, Rajiv Khandekar MBBS1
1King Khaled Eye Specialist Hospital, Riyadh, Kingdom of Saudi Arabia
2Wilmer Eye Institute of Johns Hopkins University
Background: The empiric treatment of microbial keratitis relies upon knowledge of the relative frequencies of causative organisms and their susceptibility to available antibiotics. In many populations there has been a progressive development of antibiotic resistance. The factors that influence these changes may be related to macro influences, such as access to health care, industrialization, and inpatient health care, as well as patient-specific variables such as previous antibiotic use or hospitalization.
Methods: To evaluate the recent trends in the organisms obtained from cultures of patients with microbial keratitis, as well as patterns of antibiotic sensitivity, we performed a retrospective study of all bacterial isolates from patients with microbial keratitis at the King Khaled Eye Specialist Hospital from 2011-2014.
Results: There were 3,506 bacterial isolates during the study period. Gram positive bacteria accounted for 91.4% of isolates. They mainly included Staphylococcus epidermidis 962 (47.2%), Other Coagulase-negative staphylococci 289 (14.2%), Staphylococcus aureus 237 (11.6%), and Streptococcus pneumonia 159 (7.8%). Pseudomonas aeruginosa was the most common gram negative isolate (6.0%). All tested isolates maintained 100% sensitivity to vancomycin over the study duration. Oxacillin resistance was increasingly found in S aureus (14.8% in 2011 to 27.8% in 2014. P<0.05) but was without significant change in Staph epidermidis and other coagulase-negative Staph (range 19.4-32.0%). S aureus isolates showed an increase in moxifloxacin resistance from 2011 – 2014, increasing from 0 to 14% (P=0.05). All S pneumoniae isolates were sensitive to chloramphenicol, moxifloxacin and ofloxacin; resistance to other antibiotics remained stable, including penicillin (range 24.5% - 42.9%) and erythromycin (34.0-60.0%). Pseudomonas aeruginosa isolates were resistant to ceftazidime in 5.6%, ciprofloxacin 4.9% and gentamicin 4.9%, with no significant change during the study period.
Conclusions: While the rates of antibiotic resistance are lower than reports from many European and North American cohorts, there appears to be a trend of increasing resistance to some antibiotics. This may be related to “westernization” of regional health care, with increasing access to care and utilization of antibiotics. The low prevalence of gram negative bacterial keratitis, increasing prevalence of MRSA and fluoroquinolone resistant S aureus may be taken into consideration when initiating empiric therapy.
AAO=N
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